Yaşar University

About: Yaşar University is a education organization based out in Izmir, Turkey. It is known for research contribution in the topics: Exergy & Job shop scheduling. The organization has 760 authors who have published 1436 publications receiving 20813 citations. The organization is also known as: Yaşar Üniversitesi.

A differential evolution algorithm with variable neighborhood search for multidimensional knapsack problem

Abstract: This paper presents a differential evolution algorithm with a variable neighborhood search to solve the multidimensional knapsack problem. Unlike the studies employing check and repair operators, we employ some sophisticated constraint handling methods to enrich the population diversity by taking advantages of infeasible solution within a predetermined threshold. We propose to a variable neighborhood search employing different mutation strategies to generate the trial population. The proposed algorithm in fact works on a continuous domain, but these real-values are converted to 0–1 binary values by using the sigmoid function. In order to enhance the solution quality, the differential evolution algorithm with a variable neighborhood search is combined with a binary swap local search algorithm. To the best of our knowledge, this is the first reported application of the differential evolution algorithm to solve the multidimensional knapsack problem in the literature. The proposed algorithm is tested on a benchmark instances from the OR-Library. Computational results show its efficiency in solving benchmark instances and its superiority to the best performing algorithms from the literature.

Stock-Return Volatility and Daily Equity Trading by Investor Groups in Korea

Abstract: We examine the short-run relationship between stock-return volatility and daily equity trading by several investor groups in the Korean Stock Exchange. We also investigate whether trade characteristics and trading styles can explain the potential distinct volatility effects of these investor groups. For large stocks, we find that whether a trade is a purchase or a sale and whether it is a contrarian or a momentum trade does not play a role in the relation between volatility and trading. It is the trading of informed institutional investors against non-informed individual investors that drives volatility and produces a negative volatility effect. We further show that net foreign trading has a non-decreasing impact on volatility. Our results are robust to alternative measures of volatility and obtained after controlling for a Monday effect, volatility persistency, total volume and lagged stock returns.

Factors affecting length of stay in the emergency department: A research from an operational viewpoınt

Abstract: Background: Due to the persistent increase inpatient volumes of emergency departments, improving the timeliness of emergency care delivery has become more important from an operational viewpoint. O...

Sustainable risk management: fuzzy approach to volatility and application on FTSE 100 index

Abstract: In this paper, a fuzzy volatility labeling algorithm is offered to detect the periods with abnormal activities on daily share returns. Considering the vagueness in the switches of the time periods, the membership functions of high and normal volatility classes are introduced. In the assignments, both the density structure and membership degree are used. It is believed that this algorithm may be helpful to construct different estimation models for the time periods with normal and abnormal activities. Authors offer algorithm, which can be used as a tool for sustainable risk management.